The present invention relates to lamp sockets, and more particularly to a such a lamp socket which seals out water when installed so that electric leakage is prevented and, which is easy to assemble.
Various decorative strings and Christmas tree light sets are well-known and widely used everywhere in the world, more particularly in western countries during Christmas holidays. While using these decorative lighting devices, the requirement for a safety operation is critical. UL and CSA define strict specifications on these products.
The lamp socket for a decorative string or Christmas tree light set is generally comprised of an internally threaded plastic socket body, a plastic socket cap fastened to the socket body to hold down the electric wire, and two contact metal plates mounted within a respective hole on the socket body and disposed in contact with either conductor of the electric wire. When the lamp bulb is threaded into the socket body, the tip and ring contacts of the lamp bulb are respectively connected to the electric wire through the contact metal plates. This structure of lamp socket is functional however, it has drawbacks. One drawback of this structure of lamp socket is that the socket body may expand when hot, causing the lamp bulb disconnected from the contact metal plates. Another drawback of this structure of lamp socket is that the contact metal plates may be forced to deform easily, causing a short circuit. Still another drawback of this structure of lamp socket is that rain water tends to enter the socket body causing an electric leakage. Still another drawback of this structure of socket lamp is that the screw joint of the connection between the socket body and the lamp bulb complicates the assembly process of the decorative strings or Christmas tree light sets.